Part FourSeries Episode Number: 545
World Premiere: Sat 24 Jan 1981 - 5:09pm GMT [BBC One] (United Kingdom)
First Broadcast: Wed 1 Apr 2015 - 8:30pm EDT [Retro TV]
Running Time: 24 minutes 53 seconds
7.80 Million (UK)Appreciation Index: 59 (UK)
Chart Position: 69 () (UK)
With the void collapsing around them, time is running out. Rorvik ignores the Doctor's warnings and takes a desperate gamble which could have fatal consequences.